US 8,776,565 B2 · Evaluation method of residual stress in water jet peening and method of executing water jet peening

Abstract

An evaluation method of residual stress in water jet peening includes a step of creating an analytical model including meshes according to a water jet peening (WJP) object, the shape of a nozzle, and an injection distance, a step of inputting WJP execution conditions, a step of calculating the internal pressure pBi of a cavitation bubble and a bubble number density ngi through jet flow analysis for a jet flow jetting from the nozzle, a step of calculating cavitation energy according to the internal pressure pBi of a cavitation bubble and a bubble number density ngi (S4), a step of calculating the burst energy of cavitation bubbles from the cavitation energy C, and a step of calculating the compressive residual stress of the WJP object from the collapse pressure of cavitation bubbles. Accordingly, the residual stress of the WJP object can be evaluated precisely in a shorter time.

Claims11

Dependent claims

An evaluation method of residual stress in a water jet peening, comprising:

a first step of calculating internal pressure of a bubble, included in a jet flow jetting from a nozzle used for said water jet peening, and a bubble number density through jet flow analysis in which said jet flow is analyzed according to water jet peening execution conditions;
a second step of calculating cavitation energy based on said internal pressure of said bubble and said bubble number density;
a third step of calculating collapse pressure of said bubble based on said cavitation energy;
and
a fourth step of calculating said residual stress of a water jet peening object, on which to execute said water jet peening, based on said collapse pressure of said bubbles.

2 more elements

A method of executing a water jet peening, comprising:

a first step of calculating internal pressure of a bubble included in a jet flow jetting from a nozzle used for water jet peening and a bubble number density before said water jet peening is executed for a water jet peening object, through jet flow analysis in which said jet flow is analyzed with different values of water jet peening execution conditions;
a second step of calculating cavitation energy based on said internal pressure of said bubble and bubble number density;
a third step of calculating collapse pressure of said bubble based on said cavitation energy;
a fourth step of calculating residual stress of said water jet peening object before said water jet peening is applied, based on said collapse pressure of said bubble;
a fifth step of deciding whether said calculated residual stress at a set depth from a surface of said water jet peening object is compressive residual stress;
a sixth step of storing, in a memory, values of said water jet peening execution conditions used to calculate said residual stress selected and then input, among said residual stress being compressive residual stress at said set depth and extracted in said decision in said fifth step;
a seventh step of inputting said values of said water jet peening execution conditions stored in said memory to a control apparatus for a water jet peening apparatus that executes said water jet peening for said water jet peening object;
and
a eighth step of controlling said water jet peening apparatus based on the values of said water jet peening execution conditions by said control apparatus.

6 more elements

Dependencies are inferred from the claim text.

Evaluation method of residual stress in water jet peening and method of executing water jet peening

Life of this patent

Evaluation method of residual stress in water jet peening and method of executing water jet peening

Life of this patent

Abstract

Claims11